Alkaloid

Alkaloids are a group of naturally occurring chemical compounds (natural products) that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure are also termed alkaloids.

Quotes

 * The alkaloids are bitter-tasting, natural nitrogen-containing compounds found particularly in plants. The name is derived from their characteristic basic properties (alkali-like), which are induced by the lone electron pair of nitrogen. As with acyclic amines, the (Lewis) basic nature of the alkaloids, in con junction with their particular three-dimensional architecture, gives rise to often potent phys iological activity. We have already noted some examples of this behavior in the narcotics morphine and heroin, the psychoactive lysergic acid and LSD, and the antibiotic penicillins.
 * K. Peter C. Vollhardt, Neil E. Schore (2011) Organic chemistry : structure and function 6th ed. Ch. 25 : Heterocycles